Matrix material for production of printing plates



Patented Mar. 21,

UNITED STATES. PATENT oF -ma SHERMAN oswALn THOMAS, or, ASHINGTON, nrsTR IoT or coLuMBraAssIeNon To THE AMERICAN nAIRY-sUPrLYconrAN or AUGUSTA, MAINE, A CORPORA- TION OF MAINE MATRIX MATERIAL roa rnonuc ron' or" ,ritINT Ne PLATES N0 Drawing. i Application filed J'unc"18,

This invention pertains to the production of printing plates or-surfaces, andconslsts, primarily, in a new composition of matter capable of receiving and retainingperfect impressions from type, engraved plates,

blocks and surfaces, from delicate fabrics,

and in fact from almost any object the face or surface of which bears relatively raised and depressed portions. The purposes, primarily sought and successfully attained through the use of the novel composition are:

To produce speedily and easily, and in a few minutes as comparedwith hours under existing practice, a finished printing plateor surface of high quality. This object is ,at-

tained through the use ofa composition of matter which can be molded'and brought speedily to a smooth, uniform surface capab1e.

of receiving and retaining an impression from a suitable pattern, surface or desigmhowever delicate the lines or markings of such pattern or design may be.

A further object is to produce bya single operation, a plate or printing surface complete in all respects and ready forv use, without routing and without need ofibuilding up of open spaces before casting.

The composition employed is such that it neither expands nor contracts to any appreciable extent, if at all, when poured in a ,cold

state into a mold, or upon a backing sheet, plate or block, or during or after setting therein or thereon. It is, when set, of somewhat wax-like character, more or less tough or tenacious, and unaffected by the temperature at which the molten metalor alloy for producing the printing plate is commonly poured. p

The matrix or mold produced from the composition is preferably used but once as a mold or matrix, but the composition of which it is formed may be thrown back into a suitable container, either with or without addition of fresh materials, and softened or liquefied to form new molds or matrices.

The composition is brought to fluid or. liq-s uid form without the use of heat, and as indicated, is unaffected by'heat after it has become properly set.

Another peculiarity of the co mpositionis.

1928. Serial No. 286,498.

that it may be made up in any desired quantity and stored or held ready for use, and that it remains stable and is unaffected 'by atmospheric conditions or weather changes even after quite long periods of time. It retains its capacity for receiving impressions, does not harden, does not soften, liquefy, or break down, and is ready for instant use;

v The composition is preferably made according to'the following formula,the avoirdupois scale being here understood, and a'batch or quantity of about eleven pounds total weight being assumed, though of course the aggregate weight may be varied at will Instead of commercial rubber cement the ingredients of which such cement is made may be employed, the rubber (crude rubber or caoutchouc) and the solvent being supplied in quantity suflicient to afiord in the mixture 7 the same effect as is afforded by the commercial cement.- It'is deemed preferable to employ the commercial cement because thisavoids the considerable Work and time required for the complete dissolving of the rubber, and its thorough commingling or union with the solvent. 1 A

Instead of the solvents named in the formula, benzine, chloroform and gasoline can be'used, but benzol and carbon tetrachloride are deemed best.-

In lieu of talcum, soapstone, fine chalks, or other mineral powders may be used.

The office of the rubber cement is to form a binder for'holding together the otheringredients, or the fillers of the, composition. 7

. Carbon tetrachloride causes the ingredients to mix more smoothly than they would in the absence thereof.

Benzol is used primarily as a solvent, but is also beneficial because of its tendency to expeditethe setting of the composition.

Talcum is, preferred to other powders or fillers because it gives to the composition a smooth, soft, silky, or waxy consistency and surface.

The carbon black causes a fine film to use to the surface of the molded composition,

which film tends to prevent adhesion of the form orpattern to the matrix when bein pressed against or into the composition, an facilitates detachment. of the cast plate or printing body fi'om'the mold or matrix. The. film of carbon black leaves the mold with the cast plate or printing body, and adheres to such plate or stereotype, but is, readily removed therefrom after the same has set and cooled, by application of a few drops of gaso-. line or like agent. 7

\Vhilethe proportions above given are those whichexperience has thus far shown to be best, these may be varied within reasonable limits and still give good practical results,

and it is hence to be understood thatI contemplate such variation and deem the same well within the scope of my invention and claims.

In the preparation of thecomposition I *ffind it expedient to place the several ingredients stated in the formula in a suitable mill or mixer, and to subject them to the action thereof until the several ingredients are thoroughly and intimately commingled, and the i reducible substances brought to a state of fine division. l Vhile a fluid state the composition is poured into a suitable mold, or is fiowed upon or over a backing sheet asof paper or pulp-board, a wooden block, or a metal plate or sheet, and rolled or pressed to aroduce a smooth plane surface. Plates of metal, sheets of paper, pulp-board, or the like, blocks of wood, or long strips or sheets of backing material may be thus coated with the composition, which adheres quite tenaciously to the backing, and stored for use.

Vhen it is desired to produce a'matrix or mold, a section of the backing material of suitable size, faced or coated with the com-' position set or solidified thereon and adhering thereto, is cut from the stock strip or body, is suitably impressed by the form, pattern or design, and so impressed, properly supported, and encompassed by suitable guards, receives the molten metal or alloy, which is poured upon the composition or upon the matrix or mold,jto a thickness determined by the encompassing guards, as in the usual way of pouring stereotype plates.

Nhen the metal or alloy has'completely set or hardened, it is lifted or removed from the matrix, its surface is washed with gasoline or other suitableagent, and if to be employed in an ordinary printing press, it is supplied with a support which is of the requisite thickness to bring the printing face of the cast plate, type high.

If the printing plate is to be used on a cylinder press or the like, it-is bent to the.

requisite curvature in the usualway-and by-- any customary means, or the matrix being tioned'merely to show the-adaptability of the composition to the production of plates or printing forms capable of use with different typesof printing presses or apparatus.

jIft is particularly to benoted that the composition is mixed in a coldstate, no heating of the composition being necessary in any stage, of its preparation or use. It is poured onto the backing sheets, plates or blocks, or intothe mold, while in liquid form, and sets, within an hour or two after being so poured. After being poured upon its backing and allowed to set, it may be brought to the precise thickness desired, and to asmooth, plane surface-by passing such sheets or plates between or 'under plain cold iron rollers, the composition flowing under such pressure, and

maintaining the thickness to which it is so brought. Facewise pressure, as between the bed and platen of a screw press, toggle press,

or the like, will similarly ensure smoothness of molten metal brought in contact with it in the production of the printing plate or surface. Y

The surface of plates, sheets or blocks] coated with this composition may be impressed through rolling, or through facewise pres- L sure in'a common letter-press or other similar ress. I p V I The molded and set composition requires neither dusting nor other preparation, nor any heating to cause it to take care of blank spaces, but flows automatically under pressure to fill the spaces betweenindividual. type constituting a form, or to fill larger blank spaces such as are present in engraved blocks and plates, half tones, and the like.

Thus upon pressing the pattern firmly against and embedding the raised portions of such pattern or design into the face of thecomposition, said'composition flowsinto and fills completely all'the depressions and. all the low spaces-of the pattern, form or design, and hence produces a casting or stereotype having a fine texture or surface, requiring neither filling or building up, nor routing.

In actualpractice, cast printing plates of variousdkinds have been produced ready for use, in fromthree'to five minutes, starting with the backedcomposition, and perfect impressions have been taken by such molded compositionfrom surfaces in which the lines boundary at any point or points, the excess or markings showing the design are so slightly out of common plane that reproduction would generally be deemed impossible.

Owing to the fact that the composition neither expands nor contracts during or after its molding, or its application to the backing surface, the cast plate or form reproduces absolutely the original form or pattern, and such form or pattern will fit with mathematical nieety or precision, its place in a printing press, or in a form of which it constitutes part. This is a feature of marked importance, in that wherethe plate or printing body is to be used as part of a general form or make-up, great diificulty has heretofore been experienced in causing it to register perfectly, or in positioning it to occupy precisely the space intended.

If the flow of the composition under pressure or rolling to desired thickness causes it'to pass beyond the prescribed or intended will be carefully trimmed ofi or cut away. What is claimed is:

l. A composition of matter for the produc- A tion of molds or matrices, comprising the following ingredients in substantially the proportions stated by weight (avoirdupois), to

wit: commercial rubber cement, three pounds; carbon tetrachloride, two pounds; benzol, two pounds; talcum powder, four pounds; carbon black, one-half ounce.

2. A composition for the production of matrices, comprising crude rubber, talcum powder and a small percentage of carbon black, together with'a suitable solvent for the rubber and carbon tetrachloride tofacilitate the smooth and even mixing of the solid ingredients.

3. A composition for the production of matrices, comprising crude rubber, talcum powder and a small percentage of carbon black, together with a suitable solvent for the rubber, and benzol as an aid to setting or solidifying of the composition.

a new article of manufacture, a matrix for receiving impressionsand suited for use in casting stereotype plates, comprising a plate or sheet bearing upon one face aclosely adhering layer or coating consisting of rubber, finely powdered mineral and carbon black, brought to a tenacious wax-like consistency by mixing with agents which respectively act to facilitate the smooth and even mixing of the solid ingredients and as a solvent for the rubber.

In testimony whereof I have signed my name to this specification.

SHERMAN OSWALD THOMAS. 

